Daily Archives: March 9, 2023

Standard Connectors for EV Charging

With EVs or electric vehicles becoming a trend for both individuals and commercial operations, more people are opting for them for commuting to work, school, and moving around the town. While there are tax benefits to using EVs, they also reduce our dependence on fossil fuels. Moreover, with the maturing of battery technologies, EV performance is comparable to those of vehicles with traditional internal combustion engines.

With the increasing number of EVs in use, their fundamental and foremost requirement is charging the battery. This aspect has led to a spurt in the growth of electric vehicle charging stations. Manufacturers of electric vehicles produce a range of vehicles that they base on their specific design specifications. However, charging devices need a uniform design so that any make or model of an electric vehicle can hook up for charging. At present, there are two categories of electric vehicle chargers—Level 1 and Level 2.

Level 1 chargers are available with the vehicle. They have adapters that the user can plug into a standard mains 120-Volt outlet. Manufacturers make these chargers common for use in home charging outlets.

Level 2 chargers are standalone types and separate from electric vehicles. They have adapters to plug into a 240-Volt outlet. These chargers are typically available in offices, parking garages, grocery stations, and other such locations. Homeowners may also purchase Level 2 chargers separately.

To allow any model or make of EV to connect to any Level 2 chargers, it is necessary for both the EV and the charger to use a standard connector. At present, the standard charger connector for Level 2 chargers is the SAR J1772. All the latest electric vehicles using plug-in charging use the standard SAE J1772 plug, while the charger connectors use the standard SAE J1772 adapters. These are also known as J plugs. J1772_201710 is the most current revision for the J plug specifications.

While SAE was originally an acronym for the Society of Automobile Engineers, presently they are known as SAE International. They often come up with recommended practices that the entire automobile industry accepts as standards. With the use of the standard SAE J1772 plugs, a customer purchasing an electric vehicle from any manufacturer can charge it using the same charging connector. Public electric charging stations also use the SAE J1772 chargers, and these are compatible with plugs in most vehicles from different manufacturers.

Each SAE J1772 charger has a standard coupler control system consisting of AC and DC residual current detectors, an off-board AC to DC high power stage, an auxiliary power stage, an isolation monitor unit, a two-way communication system over a single wire, contactors, relays, service and user interface, and an energy metering unit. Charging stations with J1772 connectors use a cable for charging the electric vehicle, and the rating of this cable is EVJE for 300 Volts or EVE for 600 Volts.

The EVJE/EVE cable consists of a thermoplastic elastomer jacket and insulation around a center conductor made of copper. The cable usually has two conductors of 18 AWG wire, one conductor of 10 AWG, and another conductor of 16 AWG.